digestive system Flashcards
what is the digestive system responsible for
This system is responsible for the breakdown of food into smaller soluble molecules which can be absorbed into the cells.
what is mechanical digestion
The breakdown of food by physical means such as chewing,
churning. Teeth cut and grind the food into smaller particles.
what is chemical digestion
The breakdown of food by the action of chemicals called enzymes.
Enzymes are biological catalysts. A biological catalyst is a substance that speeds up the
rate of a reaction.
explain how the mouth is adapted for digestion
The teeth and tongue help to cut and grind food into smaller particles.
salivary glands located under the tongue produce and secrete the enzyme salivary
amylase which helps breakdown starch
tongue aids in mixing the food with saliva.
explain how the oesophagus is adapted for digestion
muscle layers contract and relax rhythmically in order to push the food through the
oesophagus.
The bolus moves
down the tube by a process called peristalsis.
explain how the stomach is adapted for digestion
The stomach walls produce and
secrete a liquid called Gastric juice.(contains hydraulic acid and enzymes )which help to break down the food particles.
The thick muscular stomach wall contracts and churns the contents
of the stomach. this help to break down the food into smaller particles as well as mix
up the food with the gastric juice.
explain how the duodenum is adapted for digestion
A chemical called bile functions to breakdown fats into fatty acids.
The pancreas is also
responsible for producing and secreting two major hormones responsible for regulating the level of glucose in the blood.
explain how the small intestine (ileum or jejunum) is adapted for digestion
The tube is approximately 6m long to allow for the complete digestion of food particles as they move along the small intestines
The inner walls of the small
intestines are lined or covered with millions of finger like structures called Villi.
th shape of the villi increases the surface area for maximum absorption of the soluble food particles
explain how the large intestine is adapted for digestion
The mucous gland in the large intestine secrete mucous that
makes the stool smooth and easily excreted.
no digestion takes place here
list and explain the main processes of the digestive system
1)Ingestion
The intake of food by biting, chewing and swallowing.
2) Digestion
The mechanical and chemical processes that convert food into soluble nutrients.
3) Absorption
Occurs when the soluble nutrients are taken up by the blood stream in the intestines.
4) Egestion
Occurs when the undigested materials called faeces, are passed out of the body
through the anus.
complete
SUBSTRATE. ENZYME. PRODUCT
starch
protein
fats
SUBSTRATE. ENZYME. PRODUCT
starch salivary analyse glucose
protein pepsin amino acids
fats bile fatty acids
